21 6-14

Question 1

Adaptive defense common characteristics 5

Answer 1

1. Specific (recognizes and destroys the antigen that initiated the response)
2. Systemic (not limited to the initial infection site)
3. Memory (able to recognize the same antigen and mount a faster and stronger defensive attack)
4. Self-tolerance
5. Immunocompetency (trained to go after pathogens)

Question 2

Humoral immunity

Answer 2

Provided by antibodies produced by B lymphocytes present in the body’s humors or fluids. (antibody-mediated immunity)

Question 3

Cellular immunity

Answer 3

Associated with T lymphocytes and has living cells as its protective factor.

Question 4

Antigen

Answer 4

A substance or part of a substance that is recognized as foreign by the immune system, activates the immune system, and reacts with immune cells or their products.

Substances that can mobilize the immune system and provoke an immune response.

Nonself, antibody generating.

Mostly protein.

Question 5

Complete antigen

Answer 5

Able to stimulate the proliferation of specific lymphcytes and antibodies and to react with the activated lyphocytes and produced antibodies.

Have both immunogenicity and reactivity.

Question 6

Hapten

Answer 6

Incomplete antigens

Small molecules not capable of stimulating the immune response/making antibodies, but if they interact with proteins of the body they may be recognized as potentially harmful. (allergies, mild reactions, poison ivy)

Have reactivity but not immunogenicity

Small molecules are not immunogenic, but if they hook up with the bodies own protein then the combination may be recognized. I.e. Albumin carrying penicillin

Question 7

Antigenic determinants

Answer 7

Specific part of an antigen that are immunogenic and bind to free antibodies or activated lymphocytes.

Sequence of amino acids.

Epitopes

Question 8

MHC proteins

Answer 8

A group of glycoproteins that identify a cell as self. (major histocompatibilty complex)

Class I - found on all nucleated cells (have a flag on them that identifies as self.)

Class II - found on lymphocytes and macrophages

Question 9

Self antigens

Answer 9

MHC proteins

Question 10

APCs, Antigen presenting cells

Answer 10

Job is to find foreign invader, process some of it, stick fragment on their membrane and present it to B/T cells to mount the immune response.

A specialized cell (dendritic/macrophage/B lymphocytes) that captures, processes, and presents antigens on its surface to B/T lymphocytes.

APCs have a key role in activating B and T cells

T lymphocyte could not do anything with an antigen unless presented on APC.

Question 11

Antibody

Answer 11

Immunoglobin. Secreted from plasma cells

A protein molecule that is released by a plasma cell (a daughter cell of an activated B lymphocyte) and that binds specifically to an antigen

Question 12

Immunocompetence

Answer 12

Ability of the body’s immune cells to recognize (by binding) specific antigens; reflects the presence of plasma membrane-bound receptors

Question 13

Immunogenicity

Answer 13

The ability to stimulate specific lymphocytes to proliferate

Question 14

Reactivity

Answer 14

The ability to react with the activated lymphocytes and the antibodies released by immunogenic reactions

Question 15

Self-tolerance

Answer 15

Each lymphocyte must be relatively unresponsive to self-antigens so that it does not attack the body’s own cells.

Question 16

Humoral immunity

Answer 16

Immunity conferred by antibodies present in blood plasma and other body fluids.

Question 17

B and T cell development, maturation, activation 5

Answer 17

1. Origin: both B and T lyphocyte precursors originate in red bone marrow.
2. Maturation: Lymphocyte precursors of T cells migrate to the thymus and mature there. B cells mature in the bone marrow. During maturation, lypmphocytes develop immunocompetence/self-tolerance/get a specific assignment.
3. Seeding secondary lymph organs and circulation: Immunocompetent but still naive lymphocytes leave the thymus and bone marrow and seed the 2ndary lymph organs and circulate thru blood and lymph.
4. Antigen encounter and activation: When a lymphocyte’s antigen receptors bind its antigen, that lymphocyte can be activated.
5. Proliferation and differentiation: Activated lymphocytes proliferate and the differentiate into effector cells and memory cells. Memory cells ad effector T cells circulate continuously in the blood and lymph and throughout the 2ndary lymphoid organs.

Question 18

What do B an T cells learn in bone marrow and thymus school?

Answer 18

1. Immunocompetence (have diploma, competent to recognize specific antigen but still naïve/rookies)
2. Specific receptor (assignment)
3. Self-tolerance (unresponsive to self-antigens)
4. Accessory proteins (such as CD8)

Question 19

Positive and negative selection

Answer 19

Thymus school, but think the same happens in bone marrow.

1. Positive selection - T cells must recognize self-MHC Thymic APC and developing T cell connect - failure to recognize results in apoptosis, survivors proceed to neg selection.
2. Negative selection - T cells must not recognize self-antigens displayed on MHCs. (think autoimmune).
   Recognizing results in apotosis. Failure to recognize results in continued maturation.

Question 20

Dendritic cells as APCs

Answer 20

Superstar APC’s. Langherhans, sometimes hang out under skin in CT.

2 important things:

• Have one job - to present
• When they find an antigen they will phagocytize/process it and run to a lymph node and look for T/B cell

adaptive only

Question 21

Macrophages as APCs

Answer 21

Can present, but are in tissue mostly.

Often present antigens to T cells in order to be activated themselves - T cells will release chems and the macrophage will become an “activated macrophage”

Question 22

B-lymphocytes as APCs

Answer 22

Present antigens to helper T cells in order to obtain help in their own activation.

Question 23

How do antigens affect the adaptive defenses?

Answer 23

They can mobilize the adaptive defences and provoke an immune response. They are the ultimate targets of all adaptive immune responses.

Antigen = Antibody generating

Question 24

Describe the process of clonal selection of a B cell.

Answer 24

Army is not there from day one, but can be quickly activated.

PRIMARY RESPONSE  (first exposure)
Naïve B cell is activated when a matching antigen selects executioner/B cell

Starts making clones

Some become memory cells, some become plasma cells.

Slow - 3-6 days lag time

SECONDARY RESPONSE (subsequent exposure)

Can be years later - happens because of memory cells, bigger/immediate/longer lasting response

Question 25

B clone - Plasma cell role

Answer 25

Antibody factories, pump out antibodies for a couple weeks then die

Will attach to antigens and mark them for destruction

Question 26

B clone - Memory cell role

Answer 26

Keep ID of antigen - can mount an immediate response in the future

Question 27

Humoral - Naturally acquired Active immunity

Answer 27

Infection - contact with a pathogen

Question 28

Humoral - Naturally acquired Passive immunity

Answer 28

Antibodies passed from mother to fetus via placenta or milk.

Question 29

Humoral - Artificially acquired Active immunity

Answer 29

Vaccine - dead or attenuated pathogen (polio vaccine)

Question 30

Humoral - Artificially acquired Passive immunity

Answer 30

Injection of exogenous antibodies/gamma globulin (antivenom, hep A)

Question 31

Active humoral immunity

Answer 31

B cells encounter antigens and produce antibodies against them.

Question 32

Passive humoral immunity

Answer 32

Ready-made antibodies are introduced into your body.

Memory does not occur!